1. Field of the Invention
The present invention relates to apparatuses for forming an artificial valve to treat gastroesophageal reflux disease (GERD).
2. Description of the Related Art
The incidence of GERD has increased recently. The main symptoms of GERD are heartburn and mucosal breaks in the esophagus. Although it is a benign disease, GERD is accompanied by serious pain, and often requires treatment. The main cause of GERD is decreased function of the lower esophageal sphincter (LES) at the bottom of the esophagus followed by reflux of acid into the esophagus. GERD is usually treated by administration of acid secretion controlling agent such as proton-pump inhibitor. Moderate GERD will improve and may be treated completely by medication. If, however, the LES function is damaged seriously or if anatomic problems such as hiatal hernias exist, treatment with medication is less effective, and becomes costly over an extended period of time.
Therefore, cases of serious GERD are often treated surgically. Effective surgical methods—including Nissen fundoplication or Toupet method—are known and applied widely. With this method, the LES is wrapped by the stomach wall to improve its function. This method has been proven highly effective. Recently, laparoscopic surgery techniques were used with this method as a less invasive treatment. Because there are many patients, and GERD is a benign disease, these less invasive treatments are most desirable.
FIG. 39 depicts a tool for transoral treatment of GERD, disclosed in U.S. Pat. No. 5,887,594. This instrument (a) comprises a piercing device (e) having an elongate portion (b), a manipulation section (c) and a hook portion (d); and a securing device (i) having a connector (f), a manipulation section (g) and a securing mechanism (h). The piercing device (e) is inserted from the mouth to the stomach of a patient, and pulled up to the esophagus (k), with the hook portion (d) fixed at the upper stomach (j) thereby forming a fold of tissue (not shown).
Then, the securing device (i) is inserted into the esophagus (k) of the patient, and the securing mechanism (h) fixes the fold consisting of the upper stomach (j) and the esophagus (k). When the fold is fixed, the intermediate portion is compressed to protrude inward to form a valve (not shown).
FIGS. 40 to 44 depict another transoral treatment method of GERD, disclosed in International Patent Publication WO99/22649. An instrument (n) has a rotatable fastener head (p), which is rotatable at the distal end of a flexible tube (o), and the rotatable fastener head (p) and a portion of the flexible tube (o) that can touch the rotatable fastener head (p) have a male fastener (g) and a female fastener (r), respectively. The flexible tube (o) has a rotatable grasper (s) at the distal end, and an opening for an endoscope (t) to be inserted throughout the flexible tube (o). First, the flexible tube (o) is inserted from the mouth to the stomach of the patient. The rotatable grasper (s) is drawn into contact with a junction (v) between the stomach and the esophagus. The rotatable grasper (s) is operated to hold the junction (v). Next, the flexible tube (o) is advanced downward to suspend the junction (v). The rotatable fastener head (p) is operated to penetrate the junction (v) with the male fastener (q) to engage with the female fastener (r). Thus, the junction (v) and the middle part are compressed to be protruded inward to form a protrusion (x).
In the composition disclosed in U.S. Pat. No. 5,887,594, the hook portion d of the piercing device (e) needs to be fixed to the stomach and pulled. The gastric wall, however, is thicker than the esophagus, and is divided into three regions: the inner mucous membrane; the middle proper muscularis; and the outer serous membrane. In particular, a space between the mucous membrane and the proper muscularis has high movability. To form a protrusion into a valve, tissue including the proper muscularis should be compressed and lifted up. The hook portion (d) only takes the mucous membrane and cannot include the proper muscularis below it. Thus, the valve formed in this application is not large and thick enough to prevent reflux satisfactorily.
In the apparatus disclosed in International Patent Publication WO99/22649, the rotatable grasper (s) is integral to the flexible tube (o), which makes it difficult to touch the target tissue. The field of view of the endoscope (t) is blocked by the rotatable fastener head (p), which makes difficult for the rotatable grasper (s) to hold and suspend the junction (v) between the stomach and the esophagus.
Because the position between the rotatable grasper (s), the male fastener (q) and the female fastener (r) is fixed, the size of a protrusion (x) is limited. It is desirable, however, to form a protrusion of varying size depending on the degree of severity of GERD. The difficulty of passing food has already been reported as complication of artificial cardia in Nissen fondoplication, and is likely to happen with an excessively large protrusion (x). Even much smaller protrusion (x) is effective for the treatment of the moderate GERD. With this apparatus, treatment is not flexible enough to allow a small protrusion to facilitate food flow in the case of moderate GERD. And further, the male fastener (q) is exposed outside the device, and may damage a body lumen when it is introduced into it.